Mapping the upper mantle structure beneath the South Atlantic and the adjacent continents using full waveform tomography with geodynamic interpretations of hotspot flux and material transport in the asthenosphere.

我们建议将全波形层析成像和地球动力学正演模拟结合起来，以解决有关南大西洋地区地球动力学和演化的关键问题：(1)南大西洋羽流系统如何以及在多大程度上为大洋盆地和邻近地区的软流层提供供给？(2)沃尔维斯脊、埃滕代卡和准大陆溢流玄武岩目前的热状态是什么？(3)慢地震物质从上地幔到下地幔的路径是什么？(4)南大西洋地区从非洲到南美洲的显著地形梯度仅从下地幔结构来看是可以解释的，(5)上地幔非均质性和各向异性结构与中大西洋海脊系统和热点有何关系？全波形层析成像的使用将使我们能够从地震记录中尽可能多地利用信息。因此，我们的方法非常适合于数据覆盖率相对较低的地区，如南大西洋。矿物物理模型将使我们能够从地震观测中以热力学自洽的方式动态地推断横向温度变化的重要制约因素。地震各向异性的观测和地球动力学模拟将有助于我们进一步量化和证实我们对南大西洋上地幔的热状态和物质通量的推断。

We propose to combine full waveform tomography and geodynamic forward modelling to address key questions concerning the geodynamics and evolution of the South Atlantic region: (1) How and to which extent does the South Atlantic plume system feed the asthenosphere in the oceanic basin and adjacent regions? (2) What are the current thermal states of the Walvis Ridge and the Etendeka and Paraná continental flood basalt? (3) What, if any, is the pathway of slow seismic material from the upper to the lower mantle? (4) Is the prominent topographic gradient across the South Atlantic region from Africa to South America explicable solely in terms of lower mantle structure, or do we also find a systematic gradient in upper mantle heterogeneity across the ocean basin? (5) What is the relation of upper mantle heterogeneity and anisotropic structure to the Mid-Atlantic ridge system and hotspots? The use of full waveform tomography will allow us to exploit as much information as possible from seismograms. Our approach is thus well suited for regions with comparatively low data coverage such as the South Atlantic. Mineral physics models will allow us to infer dynamically important constraints on lateral temperature variations in a thermodynamically self-consistent way from the seismic observations. Observations of seismic anisotropy and geodynamic modelling will help us to further quantify and substantiate our inferences on the thermal state and material flux in the South Atlantic upper mantle.